## Common ground
All options refer to flat, sheet-like materials used for absorption or cleaning, but only one correctly describes regenerated cellulose sponge sheets.
## Options at a glance
**3921.14 – Made of plastic material**
- **Defining trait:** Derived from synthetic polymers (e.g., polyurethane, PVC), not natural fibers.
- **Typical examples:** Foam sponges, synthetic scrubbing pads, disposable cleaning sheets.
- **Best fit when:** The product is flexible, non-biodegradable, and made via polymerization.
**4818.90 – Made of paper or paperboard**
- **Defining trait:** Composed of cellulose fibers from wood pulp or recycled paper, often with a fibrous texture.
- **Typical examples:** Paper towels, tissue sheets, cardboard pads.
- **Best fit when:** The material is biodegradable, water-soluble, and visibly fibrous.
## Key differences
| Feature | 3921.14 (Plastic) | 4818.90 (Paper) |
|---------------------|--------------------------|--------------------------|
| Material source | Synthetic polymers | Natural wood pulp |
| Biodegradability | Low | High |
| Texture | Dense, elastic foam | Fibrous, porous paper |
| Water resistance | Often high | Low (dissolves in water) |
## How to choose
- Is the material made from petroleum-based plastic? → 3921.14
- Does it dissolve or break down when wet? → 4818.90
## Overlaps & pitfalls
Regenerated cellulose sponge sheets are **not** plastic (3921.14) nor paper (4818.90), despite being made from cellulose. They are a semi-synthetic, regenerated form of cellulose—neither fully natural like paper nor synthetic like plastic. Thus, **both options are incorrect** for true regenerated cellulose sponges. The correct HS code would be under 3920 (cellulose-based materials), but it is not listed here. If forced to choose, **4818.90** is closer in material origin (cellulose), though still inaccurate